Rotary compressor or pump.



PATEN'IED DEO. 1l, 1906.

L. H. ROGERS. VROTARY COMPRESSOR OR PUMP.

APPLICATION FILI-.1D SEPTA). 1904.

1 SHEETS-SHEET 1.

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ROTARY COMPRESSOR 0R PUMP. APPLICATION .FILED SEPT.9.1904.

4 SHEETS-SHEET 3.

40 41 mmmgs PATENTED DEO. l1, 1906.

L. H ROGBRS. ROTARY COMPRESSOR 0R PUMP.

APPLIOATIONfIILED SEPTA), 1904-. I

4 SHEETS-SHEET 4.

Ulli csse Bitume@ 3 LEBBEUS H. ROGERS, OF NEW YORK, N. Y.

ROTARY COIVIPRESSOR'OR FUIVIP. i

Speccation of Letters Patent.

Patented Dec. 11, 1906.

Application liled September 9, 1904. Serial No. 223.913.

To @ZZ whom t muy concern,.-

Be it known that I, LnBBEUs H. ROGERS, of New York, N. Y., have invented a new and useful Improvement in Rotary Com ressors or Pumps, which invention is ful y set forth in the following specification.

The invention relates to rotary air compressors or pumps, and more particularly to that class of compressors employed in connection with air-brake apparatus, although it is equally applicable to the compression of other gases and may be used as a vacuumpump.

The invention has for its object to overcome in compressors of the class above referred to the pounding and clattering noises, which are exceedingly annoying, especially on street-cars and suburban trains where such compressors are employed.

In the compressors above referred to one or more reciprocatory pistons are carried by a drum rotating within a closed cylinder, said piston or pistons having reciprocation imparted thereto 'by circular grooves in the ends of the cylinder and eccentric thereto, with which grooves the piston or pistons engage. It is exceedingly difficult to determine with precision the cause or causes of the noise resulting from the operation of this and similar compressors. Probably a part of the noise is caused by theshifting of the bearings of the pistons from the inner to the outer wall of the eccentric grooves, and vice versa, as the drum revolves. However this may be, I have discovered that if the pistons be subjected to yielding pressure on one face (preferably the rear face) the noises will be largely diminished and in 'some forms of construction entirely eliminated. Springs placed either in front of or to the rear of the pistons may be employed to exert the desired yielding pressure, but I have found it to be a more effective, convenient, and practical construction to employ some compressed fluid, as air, to exert the yielding pressure, and the construction herein described is designed more particularly to employ such a medium g but I desire it to be particularly understood that other means for exerting yielding pressure upon the face of the pistons may be employed without departing from the spirit of the invention.

Besides the means for exerting yielding pressure upon the pistons the invention includes other features of improvement, which will be hereinafter described, and specifically pointed out in the claims.

While the inventive idea involved is capable of receiving many mechanical expressions, I have shown in the accompanying drawings, for the purpose of illustration, the best embodiment of the inventionknown to me. l

In said drawings, Figure l is a perspective view of the compressor. Fig. 2 is a longitudinal vertical section on the line 2 2, Fig. 3. Fig. 3 is a transverse vertical section on the line 3 3, Fig. 2. Fig. 3a is a sectional detail on line 3a 3a, Fig. 3. Fig. 4 is a sectional fragment showing a detail of construction. Fig. 5 is a section on the line 5 5, Fig. 3. Fig. 6 is a front elevation of a block inserted into the cylinder having in its face one of the eccentric grooves for imparting reciprocations to the pistons. Fig. 7 is a side elevation of a ring-like plate secured to the end of the piston-drum. Fig. 8 isa broken section showing the manner of mounting the scraper-bars. Fig. 9 is an end elevation of a piston-drum with springs for exerting the yielding pressure upon the pistons. Fig. 1() is aperspec# tive view of the piston-drum, showing in dotted lines the position of the end plate of Fig. 7. Fig. 11 1s a diagrammatic view of a modification. Figs. 12 and 13 show further modifications. Fig. 14 is a detail.

Referring to the drawings, 6, Fig. l, indicates the cylinder, here Vshown as rovided with flanges 7, by which it may be olted in any desired position, as to a car-floor.V This cylinder may be formed in any suitable way, but preferably the barrel of the cylinder is formed integral with one of the heads 8, while the other head 9 is bolted thereto, as shown in Fig. 2. With the greatest care in packing joints leakage is liable to occur in this class of structures, and Itherefore employ the integral head S and-eliminate'much of the leakage. The integral head S is reamed out, as shown at 10, Fig. 2,leaving an interior annular shoulder 11, and extending from this annular shoulder Ato the opposite end of the cylinder are two interior grooves 12 12, Fig. 3, diametrically opposite each other.l A circular plate 13, Figs. 2 and 6, rests on the annular shoulder 11, its two ears or lugs 14 14 entering the grooves 12 12 to prevent it from turning. This plate 13 has an eccentric groove 15 formed therein, a central opening 16 for the drive-shaft, and a plurality of open- IIO ^ pistons. 6o

ings 17 for a purpose hereinafter to be described. The head 9 has on its interior face an eccentric groove 18, Fig. 2, corresponding in proportions and position to the groove 15 in the plate 13. Mounted upon the cylinder 6, and preferably cast integraly therewith, are two chambers 19 and 20, and between these is a third chamber 21, Figs. 2, 3, and 5, though, if desired, all of these chambers may be detached from the cylinder and connected thereto by suitable conduits. Chamber 19 is in free communication with the atmosphere through inlet 22, which is preferably provided with an inwardly-opening valve 22 and a strainer. This inlet-valve serves an important function when the compressor is at rest, since it prevents the escape of oil and air that may iind its way into chamber 19 as the result of back pressure from the main storage tank or reservoir. also communicates with the interior of cylinder 6 via ports 23. (Shown in dotted lines in Fig. 3 and full lines in Fig. 4.) The chamber 19 might be omitted and the cylinder communicate directly with the atmosphere via ports 23; but I prefer to em loy the chamber, as shown. Chamber 20 as a conduit 24 formed in its walls, which conduit leads from the interior of the cylinder and enters chamber 20 near its top, a port 25 connecting the top of said chamber 20 and the bottom of chamber 21 While a baflie-plate 26 depends from the topof chamber 2O between the conduit 24 and the port 25, Figs. 3 and 5. Chamber 21 is connected to the air-reservoir by pipe 21. Referring to Figs. 1, 3, and 3a, 27 is a duct in the cylinder-head 8, leading from the bottom of chamber 20 to the recess or space 10, as shown in dotted lines in Figs. 1 and 3 and in full lines in Fig. 3a, entering said space or recess by a branch duct 28. Duct 27 extends down below branch 28 and is provided at its lower end with aremovable plug 29 to enable dirt that may collect therein to be removed. Chamber 19 is provided with a duct 30 in cylinder-head 8, which duct has a plug 31, removable for cleaning purposes.

Mounted in cylinder 6 on driving-,shaft 32 is the piston-carrying drum 33, which fits snugly within the cylinder and has a plurality (here shown as four) of piston-receiving longitudinal channels 34, within which the pistons 35 reciprocate. (See Figs. 3 and 10.) Fastened to the opposite ends of drum 33 are fiat rings 3 6, Figs. 2, 7, and dotted lines in Fig. 10, which serve to close the ends of the piston-channels 34, which may be in front of the pistons at any part of the throw of the The bottom parts of the pistonchannels-t. e., the part to the rear of the pistons-are not closed, but are at all times in free communication with oil-tank 20 through ring 36, passages 17, space 10, and ducts 27 and 28. Each of the pistons 35 has on its opposite ends wrist-pins or trunnions 37,

This chamber 19v preferably carrying antifrictional rollers 38, which travel in the eccentric grooves 15 and 18, formed in the cylinder-heads 8 and 9 or in plates su kported in the cylinder adjacent to the hea s. As the drum 33 is revolved these eccentric grooves 15 and 18 serve to impart reciprocating movements to the pistons. Mounted in the grooves 12 12, formed on opposite sides of the cylinder 6, are scraperbars 39 39, (shown in Figs. 3 and 8,) the inner faces of which are flush with the interior of the cylinder 6. These bars 39 are provided with means for accurately adjusting them so as to hold them in close frictional contact with the surface of the drum 33. As here shown, said means consist of screws 40 40, threaded into the wall of 'cylinder 6 and bearing against the backs of the scraper-bars, and screws 41 41, passing through threaded .nuts 41 outside the cylinder-wall and threaded into the body of the bar. The screws 41 41 lserve to adjust the bars in orfout, while the screws 40 40 serve to lock the bars in position against the outward thrust of the drum 33.

Operation: Before starting the compressor oil is introduced into the chamber 2O through any suitable inlet, as plugged opening 42a, Fig. 1. This oil passes via ducts 27 and 28 to recessed chamber 10 in cylinder-head`8 and thence lthrou h openings 17 in plate 13 and the interior o ring 36 to the interior of drum 33, and particularly the spaces in channels 34, to the rear of pistons 35. The oil also fills the eccentric grooves 15 and 18. As the drum is revolved in the direction indicated by the arrow in Fig. 3 the piston 35 (shown at the top in said figure) is forced inward by the engagement of its trunnions with the outer camtrack of the eccentric grooves 15 18 until the drum has completed a half-revolution, after which the piston will continue to travel outward until the revolution is completed, the piston-trunnions continuing to engage the outer cam-track. This action occurs with each piston in turn. During the inward movement of the piston air at atmospheric pressure enters the piston-channel 34 in front of the piston via chamber 19, ports 23, and grooves 42, Figs. 2 and 3, formed in the cylinder-wall. n When the piston starts on its out- Ward movement, the channel 34 is cut off from grooves 42, as by lower left-hand scraper bar 39, and hence is cut off from communication with the atmosphere. After passing said scraper-bar, however, the channel is in communication with groove 43 in the cylinder-wall, and this groove communicates via duct 24, oil-chamber 20, condensing-chamber 21, and pipe 21 with any suitable air-reservoir. Vhile the fit of the parts is designed to permit as little oil as possible to pass to the front of the pistons, it has been found that more or less oil does leak in and is carried by the air up through duct 24 and into oil-chamber 20 where it strikes the baffle-plate 26 and IOC IIC

falls into the body of oil in said chamber, the I `this can be caused to occur at any desired point in the revolution of the drum by change in the position of the eccentric grooves 15 and 18. For most effective operation the eX- treme outward stroke of each piston should occur just before the piston comes opposite the upper scraper-bar 39 and itseXtreme inward stroke just before it comes opposite the lower scraper-bar 39.

It will be seen that the surface of the oil in chamber 2O is exposed to the pressure of the air in the compressed-air reservoir, and hence the backs of the pistons 35 always have an outward pressure vexerted upon them equal to that in the reservoir. The front of each piston during its outward movementfis also eX-` 1 posed to the pressure of the air in the reservoir. From this it is apparent that the work done by the eccentric grooves 15 18 on the outward or compressing stroke of the pistons is extremely small, and since this work is done by the inner wall of the grooves it follows that the reaction between the piston-trunnions and this wall is reduced to a minimum. It is believed that this, in part at least, may account for the lack of noise in the operation of the compressor. t

Some oil may still remain suspended in the air after it passes the baffle-plate 26 and reaches the chamber 21, and this is condensed and iiows back into the oil-chamber through port 25. The bottom part of duct 27 is closed by plug 29, which may be taken out to remove dirt, &c. Duct 30 and plug 31 are ernployed for the same purpose in connection with air-chamber 19. This latter duct 30 has also another use. It has been found that when the compressor stands for any length of time with pressure in the reservoir oil finds its way from the oil-chamber 20 into the airchamber 19, and the duct 30 serves the purpose of drawing this oil off, if desired.

rlhe construction shown in Fig. 9 illustrates a form' of the device in which springs l44 are placed behind the pistons 35, these springs reacting and tending to throw the pistons outward instead of the oil under air-pressure.

In Fig. 11 and Fig. 14 is shown a construction employed where it is found necessary or desirable to have the compressor and compressed-air reservoir on the same level. The pipe 21 leads from the compressor-cylinder` 6 to the reservoir 45, and the oil which ,goes over with the air will collect in the bottom of the reservoir. The air is drawn 0H for use, as

in a `cylinder 46 of an air-brake system, through pipe 47, and as it enters said pipe 47 it operates a vane 48, carrying cups 49 49,

which take up the oil Iand deposit it in the projecting open end 50 of a pipe 51, leading back to the oil-tank 2O on the compressor 6.. By this means oil is prevented from accumulating in any great quantity in the reservoir.

In Fig. 12 is shown another modification, in which springs 54 are arranged to bear against the frontof the pistons 35 and tend tol press them inwardly.; These springs 54 may be placed in any position where they will exert a yielding opposition to thel outward movement of thepistons 35 and are here shown as bearing on4 the front of the trunnions of said pistons. l

In locations where the compressed-air reservoir can be placed above the level ofthe cylinder 6 the chambers 20 and 21 may be dispensed with, if desired. Such a construction is shown in Fig. 13, in which the air and oil is forced from the cylinder 6 via pipe 55 to the compressed-air reservoir 56, and the oil returns to the cylinder 6 via the pipe 57.

The driving-shaft` 32 may pass entirely through both heads 8 and 9. and be provided with suitable packing to prevent leakage, as in Fig. 5; but preferably the end of the shaft simply takes bearingat 8 in solid head 8, Fig. 2, and packing is only necessary at 52, where it passes through head 9.

What is claimed is-.,

1. In a rotary compressor or pump, a cylinder, a rotary drum therein having a pistonchannel, a reciprocating piston in said channel, a liquid-containing reservoir in open communication with one vendof said channel and open to the opposite end of the said channel during the delivery-stroke of the piston, and means ycutting off said communication on the intake-stroke of the piston.

2. In a rotary compressor or pump, a compressed-air reservoir, a reservoir containing oil, a cylinder, a rotary drum therein having a piston-channel, a reciprocating piston in said channel, a conduit leading from the front of said piston-channel to the compressed-air reservoir, a conduit leading fromlthe oil-reservoir to the rear of the pistonchannel, and an open communication between said air and oil reservoirs.

3. In a rotary compressor or pump, a cylinder, and a compressed-air reservoir, an oilchamber, and a chamber open to the atmosphere, a port from the latter chamber to the cylinder7 a conduit leading from the cylinder throughthe oil-chamber to the compressedair reservoir, a drum rotating insaid cylinder, said drum having piston-channels, pistons therein, and conduits' connecting the rear and front ends of the piston-channels through said oil-chamber on the. deliverystroke of the pistons.

4. In a rotary compressor or pump, a cylinder, a compressed-air reservoir, `a rotary drum having a piston-channel, a reciprocating piston in said channel and conduits con- IOO los

IIO

- constantly subjecting the rear of said pistons in said channels to the pressure in said reservoir, and means subjecting the front of said pistons to the opposing pressure in said res-` ervoir during the delivery-stroke thereof.

6. In a rotary compressor or pump, a compressed-air reservoir, a cylinder, a rotating drum therein having piston-channels deliver- `ing to said reservoir, aplurality'of reciprov eating pistons in said channels,.a conduit from said cylinder to said reservoir, an oilchamber forming part of said conduit, anda conduit from-said oil-chamber to the rear of said pistons.

7. In a rotary compressor or pump, a compressed-air reservoir, a cylinder, a rotating drum therein having piston-channels delivering to said reservoir, a plurality of reciprocating pistons in said channels, a conduit from said cylinder to said reservoir, an oilchamber and a condenser-chamber'forming part of said conduit, and a conduit from said oil-chamber tothe rear of said pistons.-

8. In a rotary compressor or pump, a cylinder, a compressed-air reservoir, a conduit conducting air from said cylinder to said reservoir, an oil-chamber and a condenser forming part of said conduit, a rotating drum in -said cylinder, a plurality of radial channels in said drum delivering to said reservoir through said oil-chamber, reciprocating pistons in said channels and a conduit from the oil-chamber to said channels at the rear of said'pistons.

9. In a rotary compressor or pump, a cylinder having its barrel integral With onehead thereof, a recessed chamber in said head, an oil-chamber, a duct leading from said oilchamber to said recessed chamber, a source of compressed gas communicating With and above the bottom ofsaid voil-chamber, a rotating drum in said cylinder, a piston carried by said drum, and a conduit from said recessed chamber to the rear of said piston and a second conduit leading from said oilreservoir to said cylinder and open kto the front of said piston during transfer of fluid out of the piston-channel.

10. In a rotary compressor or drumya cylinder having its barrel integral With one head thereof, a recessed chamber formed in said head, a stationary plate forming one Wall of said chamber and having a groove formedin its face eccentric to said cylinder, a corresponding eccentric groove in the other end of the cylinder, a drum rotating in said cylinder, pistons carried by said drum and engaging said eccentric grooves, and an oil-chamber communicating With the spaces in rear of said pistons through said recessed chamber. '11. In a rotary compressor or pump, a cyl'- inder, a rotating drum in said cylinder having longitudinal channels therein, reciprocating pistons in said channels,' annular plates closing the ends of said channels forward of said pistons butleavin the ends of the channels open to the rear o the pistons, and trunnions on said pistons passing through the openings in said plates and engaging cam-grooves in the ends of said .cylin- 12. In an air-compressor, a compressioncylinder having a piston-channel, a piston Working therein, a compressed-air reservoir `in open communication With said cylinder,

a chamber communicating With said cylinder and havin a port leadin to the atmosphere, an inward y-opening va ve controlling said port, and an oil-reservoir in open communication With said compressed-air reservoir and With the space to the rear of the said piston.

, 13. In arotary compressor, a cylinder, a

rotary drum in said cylinder, a reciprocating piston moving in a channel in said drum, means closing a portion of the ends of said channel, an oil-reservoir, and conduits for placing the opposite ends of said piston-channel in communication AWith said oil-reservoir on the delivery-stroke of said piston.

14. In a rotary compressor, a cylinder, a rotary drum in said cylinder having a plurality of longitudinally-extending piston-channels formed therein, pistons in said channels having cam engagement exterior to the drum for reciprocating said pistons, means closing that portion of the ends of said channels Which lies forward-of the front or Working face of said istons, an yoil-reservoir, and conduits for p acing the opposite ends of said piston-channels in communication with said oil-reservoir on the delivery-stroke of said pistons.

15. In a rotary compressor, a cylinder, a rotary drum in said cylinder having a plurality of longitudinally-extending piston-'channels formed therein, pistonsin said channels having cam engagement exterior to the drum for reciprocating said pistons, annular plates or rings closing that portion of the ends of said channels which lies forward of the front or Working face of said pistons, an oil-reservoir, and conduits for placing the opposite vends of said piston-channels in communication With saidoil-reservoir on the delivery'- stroke of said pistons.

16. In a compressor, a compression-cylinder, a plurality of pistons playing therein, a compressed-air reservoir and an oil-reservoir communicating With each other, and one conduit leading from the oil-reservoir to the rear of said pistons and the other leading from said oil-reservoir to said cylinder and IOO IIO

open to the front of said piston during the delivery of fluid out of the piston-channel.

17. In a rotary compressor or pump, a compressed-air reservoir, a cylinder, a piston-carrying revoluble drum therein, conduits connecting said cylinder and reservoir, one of said conduits conducting compressed air to said reservoir and the other conducting liquid from the reservoir to the cylinder, and mechanically-operated lifting means for transferring said liquid in the reservoir to said liquid-conduit.

18., In a rotary compressor or pump, the combination of a cylinder, a rotary drum in said cylinder and concentric therewith, reciprocating pistons carried by said drum, an

oil-chamber, a conduit fromsaid oil-chamberto the rear of said pistons and a second conduit leading from said oil-reservoir to said cylinder and open to the opposite faces of said pistons during transfer of fluid out of the piston-channels.

19. In a rotary compressor or pump, a cyl inder, a revoluble drum in said cylinder having longitudinal channels therein and communicating with each other at their inner ends, reciprocating pistons in said channels,

and annular plates closing the ends of said channels forward of said pistons in all positions thereof.

20. In a rotary compressor or pump, the combination of a casing having an inlet and outlet, a revoluble drum in said casing, a reciprocating piston in said drum, a cam-track eccentric to said drum, piston-trunnions guided by said track, and means for subjecting the rear of said piston to the fluid-pressure of the compression-stroke during a complete revolution of said drum.

21. In a rotary compressor or pump, the combination of a casing, a drum revolubly mounted in said casing and having Aa pistonchannel and a reciprocating piston in said channel, said casing having an inlet and outlet, said outlet being in permanent open communication with both ends of said pistonchannel on the delivery-stroke of said piston.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

LEBBEUS II. ROGERS. Witnesses:

HIRAM D. ROGERS, HIRAM D. ROGERS, Jr. 

